Hack saw



July 30, 1929. w, AFFQ D 1,722,316

HACK SAW iled March 16, 1928 INVENTOR.

A TTORNEYS Patented July 3Q, 1929.

nane rnn' eerie.

JAMES WEBB SAFFOLD, OF CLEVELAND, OHIO.

HACK SAW.

Application filed March 16, 1928; Serial N'o. 262,083.

The pr sent invention, relating as indicated to hack saws, is moreparticularly directed to an improved hack sawrhaving a frame permittingof placing a considerable tension on the hack saw blade withoutdistortion of the frame. A further object of the invention is theprovision of a simple and extremely rigid two-part frame construct-ionwhich may conveniently and quickly be adjusted to receive and tensionthe blades, as well as to disengage the same when desired. A furtherobject of the invention is the provision of simple blade retaining meansin opposed parts of the frame, together with beams for mounting theblades in either of two planes at right angles to each other and tomount blades in parallel planes for producing parallel saw slots whendesired.

To the accomplishment of the foregoing and related ends, said invention,then, consists of the means hereinafter fully described and particularlypointed out in the claims; the annexed drawing and the followingdescription setting forth in detail certain mechanism embodying theinvent-ion, such disclosed means constituting, however, but one ofvarious mechanical forms in which the principle of the invention may beused.

In said annexed drawing Fig. 1 is a side elevation partially in sectionof the frame contemplated by the present invention; Fig. 2 is asectional View taken substantially on the line 22 of Fig. 1, and lookingin the direction of the arrows; Fig. 8 is an end elevation'of theprojection extending from the handle member showing a section of a bladein position thereon; Fig. 4 is a section taken substantially on the line44: of Fig. 1, and looking in the direction of the arrows; Fig. 5 is asectional view showing the saw of the present invention in use to cut aslot in a piece of work; Fig. 6 is a similar view showing the saw in.use to make a cut spaced a given distance from the edge of a piece ofwork; Fig. 7 is a sectional view taken substantially on the line 77 ofFig. 3, and looking in the direction of the arrows; and Fig. 8 is asimilar view on line 8-8 of Fig. 4 showing a modification of the sawengaging means.

Numerous attempts have been made to produce hack saws having a two-parttelescoping frame for the purpose, of course, of providing a tensioningmeans for the blades which will be really effective in placing theseunder a considerable tension. The difliculty which has been experiencedin all saws of this type, however, has been when ordinary circulartubing and circular parts have been telescopically engaged the stressplaced upon these members when a saw blade is tensioned in the frame hasbeen so severe that the frame is bowed, with resultant rapid wear onengaging parts of the two members, and with the difficulty that afterthe telescoping parts have thus been strained it has been very diliicultto adjust them with respect to each other. As a result of thesedifficulties the ordinary standard hack saws which are in use areordinarily formed with a rigid non-telescoping frame and an adjustmentfor the saw blade is provided in one of the arms of the frame, whichadjustment is ordinarily inadequate to properly tension the blade. Thepurpose of the present in-. vention is to provide a frame having twotelescoping members of extreme rigidity and of such character that theordinary strains imposed upon these two members at the points ofengagement are insufficient to overcome the natural rigidity of themembers so that the twoparts of the frame remain in the predeterminedand desired relationship to each other, while atthe same time permittingan extremely severe tension to be placed upon the blades, minimizlng therisk of breakage and improving the quality of the work which the saw iscapable of performing.

My improved saw consists of two cooperative members 1 and 2 which aretelescopically engaged with each other, and which constitute the frame,the members being provided with extensions 3 and 4, respectively, whichextend toward each other in the same plane, and between which the sawblade may be mounted. The member 1, which is the handle member of theframe, is provided with a handle 5 and with. a tubular extension 6therefrom, within which is telescopically received the member 2. Thesetwo members are formed to provide a maximum strength and resistance tobending in the plane of the saw, since the stress imposed upon thesemembers when the saw blade is placed under tension tends to bend the twomembers upwardly and away from the saw blade. Accordingly the member 6,which is of tubular form, has its maximum depth in the plane of the saw,as shown in Fig. 2, being substantially circular with flattened sides incross section, while the member 2 is similarly formed with its maximumdepth in the plane of the saw, and is roughly of I-beam cross-section,the portions 7 and 8 of the member corresponding to the flanges of anI-beam being formed as parts of the same cylinder, and being threaded.

These two members are engaged as indicated in Fig. 1 and are locked in.any desired engagement by means of a hand .nut 9, which abuts againstthe end of the tubular member 6 and engages over the threaded flanges 7and 8 of th other member .2. By rotating the nut in one direction or theother the members may be brought closer together or may be spaced apartfor the purpose of applying tension to a saw blade held between thealigned extensions 3 and 4.

The extensions are provided with engaging projections in the form ofpins 10 and 11, the pins 10 being those lying in the plane of the sawand projecting from the upper and lower faces of the extensions 3 and4c. The pins 11 are those which project from the lateral faces of thetwo extensions, and by this arrangement of projections it is possible toengage a saw blade on any of the faces of the extensions so that the sawblade will lie in planes either parallel or at right angles to the planeof the saw, as may be desired.

The pins are engaged in the extensions in the manner shown in Figs. 7and 8. An opening is provided through the extension into which the pinis driven with a reasonably tight fit, after which the ends are bentover the projection toward the end of the frame, and this angulardisposition of the projections serves the double purpose of causing theblade which is engaged thereover to be drawn tightly against the suyporting face of the extension when the plate is tensioned in the frame,and to be forced of]? from the projection when the two parts of theframe are caused to approach each other, thus making it possible toautomatically disengage a blade when its removal is desired. 7

In Figs. 3, 4 and 8 I have shown one of the series of pins 15 providedwith a threaded and prolonged extension 16, on which are adapted to bereceived spacing washers 17. These washers are of the same thickness,and their thickness may be ordinary fractional units either of an inchor centimeter, as desired, to provide for the convenient mounting ofmultiple saw blades for the cutting of spaced parallel slots at givendistances apart. The washers, together with the saw blades properlyspaced, are then clamped in this relationship by a convenient wing nut18 in the manner indicated, and the placed sawsmay then be used eitherfor sawing a slot a given distance away from the side 19 of an article(see Fig. 6), in which case the outer saw blade 20 merely serves as aguide for properly positioning the operating saw blade 21, or the twosaws 20 and 21 may be used as indicated in Fig. 5 for cutting theparallel slots spaced a predetermined distance apart.

The advantages of my improved construction are, first, its rigidity, andhence its long life; second, the convenience of use and the easymounting and dismounting of saw blades; third, the extreme tension whichmay be placed upon the blades; and fourth, the features which permit theuse of multiple blades for producing parallel slots having apredetermined spacing.

Other modes of applying the principle of my invention may be employedinstead of the one here explained, change being made as regards themechanism herein disclosed, provide l the means stated by any of thefollowing claims or the equivalent of such stated means be employed.

I therefore particularly point out and dis tinctly claim as myinvention 1. A hack-saw comprising a handle member provided with atubular extension of circular cross-section with flattened sides, an endmember provided with an extension of general Lbeam cross-section, theflanges of said I-beam being formed as parts of a cylinder and beingthreaded, a nut engaging upon said threaded flanges of said end memberand abutting against the end of said tubular member, and said membersbeing provided with aligned extensions, each adapted to receive the endof a saw blade.

2. A hack saw frame comprising members adjustable toward and away fromeach -other, a rectangularly shaped projection on each of said members,said pro ections extending toward each other and in alignment,oppositely inclined pins provided on one side of each said projections,threaded studs on the opposite side of each projection, and a pluralityof removable spacing members and an adjusting nut on each of said studs.

Signed by me, this 12th day of March,

JAMES VEBB SAFF OLD.

